/**
 ******************************************************************************
 * @file notfs_utils.c
 * @author leven
 * @brief
 ******************************************************************************
 */

#include "notfs.h"

uint32_t notfs_timestamp(void)
{
    extern uint32_t mw_get_current_timestamp(void);
    return mw_get_current_timestamp();
}

uint32_t notfs_crc32(uint32_t crc, const uint8_t *data, size_t len)
{
    /* crc table generated from polynomial 0xedb88320 */
    static const uint32_t table[16] = {
        0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
        0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
        0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
        0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c,
    };

    crc = ~crc;

    for (size_t i = 0; i < len; i++) {
        uint8_t byte = data[i];

        crc = (crc >> 4) ^ table[(crc ^ byte) & 0x0f];
        crc = (crc >> 4) ^ table[(crc ^ (byte >> 4)) & 0x0f];
    }

    return (~crc);
}

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